Selector mechanism for chagne speed hub gears of cycle wheels



W. BROWN Sept. 4, 1951 SELECTOR MECHANISM FOR CHANGE SPEED HUB GEARS OF CYCLE WHEELS Filed April 2, 1949 m /////K ////VM N AWNQN Q- A 7/ Q x 6 7 d m In.

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. INVENTOR Villiam Brown ATTORNEY Patented Sept. 4, 951

SELECTOR MECHANISM FOR CHANGE SPEED HUB GEARS OF CYCLE WHEELS William Brown, Nottingham, England Application April 2, 1949, Serial No. 85,198 In Great Britain April 26, 1948 4 Claims.

This invention relates to selector mechanism for change speed hub gears of cycle wheels of t e kind com rising epicyclic gearing having an axially movable selector member arranged to transmit the drive irom an input member alternatively to the planet carrier or to the annulus of the epicyclic gear train through complementary engageable elements on the planet carrier and annulus, the selector member for one change of gear ratio moving axially out or engagement with the set of such elements on the planet carrier and into engagement with another set of such elements on the annulus. Such change of rat o is to be found in most hub gears whether having 2, 3 or more alternative gear ratios.

The disadvantages at present found in all epicyclic hub gears having such change of ratio are, firstly, that a neutral position must be pro= vided to prevent locking and resultant damage during axial travel of the selector member from engagement with the set of complementary engageable elements on the planet carrier or an- IllllllS before coming into engagement with the other set of elements on the annulus or planet carrier respectively so that the total axial travel of the selector member includes the distance of travel through such neutral position as well as the separate distances of travel respectively out of full engagement with one set of complementary elements and into full engagement with the other set. Secondly, due to the fact that the relative angular positions of the said sets of complementary engageable elements are changeable and undetermined by virtue of the gearing between them, the selector member is more likely, in its axial movement, to abut against, instead of entering into correct engagement with the next set of complementary engageable elements towards which it is being moved. Such abutment prevents axial movement of the selector member and may result in straining of the selector-moving mecha nism with subsequent incorrect relative positioning of the selector member or may cause damage of some other kind.

The object of the present invention is an improved construction of selector mechanism for a change speed hub gear of the kind referred to and in which the aforesaid disadvantages are eliminated.

According to the invention, selector mechanism for a change speed hub gear of the kind referred to is characterised in that the complementary engageable elements on the annulus constitute with the axially slidable selector member a unidirectional clutch with the parts thereof having complementary lateral chamfer to permit axial non-clutching engaging movement of the selector I member with such elements, the selector member being axially longer than the spacing between the complementary enga eable elements on the planet carrier and annulus respectively.

According to one embodiment of the invention selector mechanism for a change speed hub gear of the kindreierred to is characterised in that the complementary engageable element on the annulus comprises at least one pawl serving only such Iunction and adapted to be tripped by lateral abutment oi the selector member therewith, or to over-ride the selector member, whereby overlapping progressive axial disengagement and axial positioning for engagement OI the selector member with the said complementary engageable elements on the planet carrier and annulus respectively, or axial engagement and axial posi tioning i'or disengagement may occur without locking of the epicyclic gearing.

In the accompanying drawings:

Fig. i is an axial sectional elevation taken on line XOY of Fig. 2 of one example of selector mechanism made in accordance with this invention and as applied to a 2-speed cycle wheel hub gear;

Fig. 2 is a cross section on line A-A of Fig. 1;

Figs. 3 and 4 are fragmentary views showing the action of the selector and pawl shown in Figs. 1 and 2;

Figsb and 6 are similar fragmentary views showing a modification.

As shown in Fig. l the epicyclic gear system consists of the fixed member I on which is formed the sun pinion 2, a planet carrier 3, with planet pinions 4, mounted therein by pins 5 and having dog members 3a on its face (forming the set of complementary engageable elements on the planet carrier), an internally toothed annulus t carrying one or more pawls 1 (forming the other set of complementary engageable elements. on the annulus) mounted on pins 8 and operated in an inwards direction by springs 9 so as to, project into the bore of annulus 6. Sliding on. the fixed member I is a sleeve It carrying a selector member ll, operated in one direction by the key I2 and rod 13 and in the other direction by the spring l4 and thrust ring It. An input member it is journaled by the ball race ii to the fixed bearing member 18 and has prongs 16a cut thereon to engage with the selector member H. on the input member is journaled the bearing cup Iii for the hub shell 28. The remainder of the hub is omitted for clarity.

The operation of the device is such that when no pull is applied to the rod [3, the sleeve l0, selector member H and thrust ring l5 take up the position shown with the selector member ll engaging the dogs 3a so that the drive passes from the input member 15 through the selector member H and dogs 3a to the planet carrier 3, the annulus 6 being driven in the same direction but at a higher speed. When a pull is applied to the rod 13 the selector member II is moved to the right so as to disengage from the planet carrier dogs 3a. No neutral position is provided asodcv 3 for the selector member II so that, if such axial movement of the selector member occurs while the gear is rotating, the faster-moving annulus pawls 1 over-ride the selector member H (as shown for the dotted position of the selector in the lower part of Fig. 2) until such time as the selector member I 1 leaves the dogs 3a where upon it will engage and take up the drivewith the annulus pawls 7 as shown in the full-lined position of Fig. 2. It will therefore bese'en that the selector member Ii being axially longer than the spacing between the dogs 3a and the .pawls 1 respectively while moving progressively out of engagement with the dog's 3a, also moves simultaneous and progressively towards its position 'ior full ement with the pawrs '7, though actual driving engagement with such pawl's does not occur until the selector member disengages Efrem the dogs ea. Should a pull be applied to the rod 13 whilst the gear is stationary and at such time as the pawls "i are opposite the limbs of the selector member M then the ehamfer i to on the selector iinrbs will raise each 'of :the paw'l's 7 by abutting on its owner as shown in Fig; 3 so allowing the selector member to move axially in the directionof the arrow until it lies wholly beneath the pawl as shown in l.- On ap plying torque to the input member selector member II will rotate din-beneath the paw-1 so allowing it to drop into its operating positionto engage With one or other of the seieetor limbs and so take up the drive. Alternatively the pawl can be eham fered for the same: purpose as show-h at 'i-a in Figs.-'5 and 6.

It will be seen therefore that, whether the is rotating or stationary, the selector n ean be moved 'from the planet earrie" a so as to enga e the pawl's- 7 of the Without risk of jamming and without the need ror-a'neo tral position for the selector nember between the two engaging positions. Further, Whilst the selector member ii! is engaged with the dogs do it cannot-be 'e'ng'aged in a driving member with the complementary engaging elements of dogs and powl's. @bvliou'sly also, as there is no neutral position for the selector between engagement with the dogs 3a and with the pawls 1, torque can always be transmitted by it lib/bile or the other of them.

claim is:

1 A selector mechanism for a change speed cycle gear hill) of the kind having an epicyclic gear train including a sun pinion, a planet carwithplanetary pinions, an annulus and an axially movable selector member with radially projecting arms for engaging an input member for drive alternatively 'with the planet carrier or the annulus comprising in combination at least one spring loaded pawl mounted onsaid annulus, at least one *di i-vm'g dog onthe end of said planet "carrier,- the axially movable s'ele'e tor being adapted to engage said planet o er dog and said annulus pawl, said pawl engaging the selector member to t ansio'i it arr-re when disengaged iron the planet carrier to over ride said selector member when engagedwith said planet carrier dog.

2. selector mechanism according to claim 1 in Which-said spring loaded is a nd-said selector member have relative l'a-o'era sham-foreclfaces, so that when the-selector member moved-axial- 1y away from the'pla-riet carrier, the edge of the selector -1riembe1-nray1pass eer the edge of the pawl to trip the same so that it does not obstruct further axial movement-oi the seieo'tor member.

3. A "selector mechanism io'r a change speed cycle gear hub of the hind having an epi'cyoli'c gear train including a pinion, a planet -carrier with planetary 'pirrions, an annulus and an axially movable selector member with radially projecting arms for engaging aninput rnei 1 for drive alternatively with the plan's-t or the'annulns, col-zrprising incombination sp il'lg" sense with the pawls 1 since they will-be moving faster and ever-aide said selector mein-ber. soon as the selector member clears the dogs 3a it will then take up -d ve w t pawls "L For the-return movement release o- -ne pull on the rod 12- allow the spring i l. to move the selector member in I engagement with the relatively moving --'do'gs o-f the Ep-l'anet merrier. Jamming cannotocciir While the elector n beris still axial-1y overlapping with e 1 because, already stated; such "p ils will override the selecto'r as soon-as'rotation 'of the-selector member is determined by engagement with the dogs to;

The advantages obtainable from the construction are, interali'a, that there is no qJessibiIity -e-f damage-due to chance engagementof the selector with the fac'e 'of the pawls, norof jamming due to contact of the selector with the pawls While engaged with the dogs "of the planet carrier. Again, since there is no need for aneutral position for the selector member, the axial space hitherto required for such neutral position as well as part of the separate distance of travel for such selector memberoutof'fullengagen'fent with loaded pawls mounted on the annulus a-nd dri-ving dogs on the of the annulus on the end of said planet carrier, the axiall movable selector being adapted-to-engage with said pla-net oar rier driving dogs and said annulus pawls, said pawl-s engaging the selector "member to irransmit drive whendiseng'aged in the planet carrier-drivingdegs and to eve do said selector gnember when engaged with said planet carrier og-s.-

4. :A selector mechanism according to claim "'3 in which said-:s'prmg loa'ded pawls said-selec tor member have relative laterally chamfered faces, so that when the -sele'ctormember is-moved axially away i-rorn theplanet carrier, the edges of :the selectormember-may :pass under theeorre= sponding edges of the ands totrip "the same, that they do not obstruct further axial =in'o vem'e'nt of the selector -nieiiiber.

W lLLIAM BROWN.

@ES CET ED The following references are of record in the file-of this patent:

UNITED STATES PKTENTS Number Name Date 2 ,1}; 8,600 Brown in. i Aug. 8, -l 939 2, -2 3 1,4-1 1' Lawrence Feb. 11 1-, V1941 2,3 79,024 l helander June .26, 19.45

FOREIGN Number Country, Date 234,230 Switzerland Jania, 194's *5 19945; greatiterrcain 'ojct. 9/1939 567,340" "oreatsrirain "Fb'. mars 

